Skip to contentSkip to conversation

xen/pcifront: Remove usage of struct timeval

PATCH In review Tina Ruchandani 3 participants 5 messages May 11, 2015

Subsystems (3)
lore
Share & tools
lore
#0 lore raw

PATCH 1/1 xen/pcifront: Remove usage of struct timeval

struct timeval uses a 32-bit field for representing seconds, which will overflow in the year 2038 and beyond. This patch replaces struct timeval with 64-bit ktime_t which is 2038 safe. The patch is part of a larger effort to remove instances of 32-bit timekeeping variables (timeval, time_t and timespec) from the kernel.

---
 drivers/pci/xen-pcifront.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
drivers/pci/xen-pcifront.c +6 -5
index 7cfd2db..43d1d6c 100644
@@ -20,6 +20,7 @@
 #include <linux/workqueue.h>
 #include <linux/bitops.h>
 #include <linux/time.h>
+#include <linux/ktime.h>
 #include <xen/platform_pci.h>
 
 #include <asm/xen/swiotlb-xen.h>
@@ -115,7 +116,7 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 	evtchn_port_t port = pdev->evtchn;
 	unsigned irq = pdev->irq;
 	s64 ns, ns_timeout;
-	struct timeval tv;
+	ktime_t tv;
 
 	spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
 
@@ -132,8 +133,8 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 	 * (in the latter case we end up continually re-executing poll() with a
 	 * timeout in the past). 1s difference gives plenty of slack for error.
 	 */
-	do_gettimeofday(&tv);
-	ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
+	tv = ktime_get_real();
+	ns_timeout = ktime_to_ns(tv) + 2 * (s64)NSEC_PER_SEC;
 
 	xen_clear_irq_pending(irq);
 
@@ -141,8 +142,8 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 			(unsigned long *)&pdev->sh_info->flags)) {
 		xen_poll_irq_timeout(irq, jiffies + 3*HZ);
 		xen_clear_irq_pending(irq);
-		do_gettimeofday(&tv);
-		ns = timeval_to_ns(&tv);
+		tv = ktime_get_real();
+		ns = ktime_to_ns(tv);
 		if (ns > ns_timeout) {
 			dev_err(&pdev->xdev->dev,
 				"pciback not responding!!!\n");
Signature · 1 line
2.2.0.rc0.207.ga3a616c
#1 lore raw
Quoted 8 lines · Tina Ruchandani

struct timeval uses a 32-bit field for representing seconds, which will overflow in the year 2038 and beyond. This patch replaces struct timeval with 64-bit ktime_t which is 2038 safe. The patch is part of a larger effort to remove instances of 32-bit timekeeping variables (timeval, time_t and timespec) from the kernel.

Looks OK to me.

Quoted 50 lines
---
 drivers/pci/xen-pcifront.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
drivers/pci/xen-pcifront.c +6 -5
index 7cfd2db..43d1d6c 100644
@@ -20,6 +20,7 @@
 #include <linux/workqueue.h>
 #include <linux/bitops.h>
 #include <linux/time.h>
+#include <linux/ktime.h>
 #include <xen/platform_pci.h>
 
 #include <asm/xen/swiotlb-xen.h>
@@ -115,7 +116,7 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 	evtchn_port_t port = pdev->evtchn;
 	unsigned irq = pdev->irq;
 	s64 ns, ns_timeout;
-	struct timeval tv;
+	ktime_t tv;
 
 	spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
 
@@ -132,8 +133,8 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 	 * (in the latter case we end up continually re-executing poll() with a
 	 * timeout in the past). 1s difference gives plenty of slack for error.
 	 */
-	do_gettimeofday(&tv);
-	ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
+	tv = ktime_get_real();
+	ns_timeout = ktime_to_ns(tv) + 2 * (s64)NSEC_PER_SEC;
 
 	xen_clear_irq_pending(irq);
 
@@ -141,8 +142,8 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 			(unsigned long *)&pdev->sh_info->flags)) {
 		xen_poll_irq_timeout(irq, jiffies + 3*HZ);
 		xen_clear_irq_pending(irq);
-		do_gettimeofday(&tv);
-		ns = timeval_to_ns(&tv);
+		tv = ktime_get_real();
+		ns = ktime_to_ns(tv);
 		if (ns > ns_timeout) {
 			dev_err(&pdev->xdev->dev,
 				"pciback not responding!!!\n");
Signature · 1 line
2.2.0.rc0.207.ga3a616c
#2 lore raw
In reply to Tina Ruchandani
Quoted 8 lines · Tina Ruchandani

struct timeval uses a 32-bit field for representing seconds, which will overflow in the year 2038 and beyond. This patch replaces struct timeval with 64-bit ktime_t which is 2038 safe. The patch is part of a larger effort to remove instances of 32-bit timekeeping variables (timeval, time_t and timespec) from the kernel.

Looks OK to me.

Quoted 50 lines
---
 drivers/pci/xen-pcifront.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
drivers/pci/xen-pcifront.c +6 -5
index 7cfd2db..43d1d6c 100644
@@ -20,6 +20,7 @@
 #include <linux/workqueue.h>
 #include <linux/bitops.h>
 #include <linux/time.h>
+#include <linux/ktime.h>
 #include <xen/platform_pci.h>
 
 #include <asm/xen/swiotlb-xen.h>
@@ -115,7 +116,7 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 	evtchn_port_t port = pdev->evtchn;
 	unsigned irq = pdev->irq;
 	s64 ns, ns_timeout;
-	struct timeval tv;
+	ktime_t tv;
 
 	spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
 
@@ -132,8 +133,8 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 	 * (in the latter case we end up continually re-executing poll() with a
 	 * timeout in the past). 1s difference gives plenty of slack for error.
 	 */
-	do_gettimeofday(&tv);
-	ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
+	tv = ktime_get_real();
+	ns_timeout = ktime_to_ns(tv) + 2 * (s64)NSEC_PER_SEC;
 
 	xen_clear_irq_pending(irq);
 
@@ -141,8 +142,8 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
 			(unsigned long *)&pdev->sh_info->flags)) {
 		xen_poll_irq_timeout(irq, jiffies + 3*HZ);
 		xen_clear_irq_pending(irq);
-		do_gettimeofday(&tv);
-		ns = timeval_to_ns(&tv);
+		tv = ktime_get_real();
+		ns = ktime_to_ns(tv);
 		if (ns > ns_timeout) {
 			dev_err(&pdev->xdev->dev,
 				"pciback not responding!!!\n");
Signature · 1 line
2.2.0.rc0.207.ga3a616c
#3 lore raw
In reply to Tina Ruchandani
Quoted 6 lines · On Monday 11 May 2015 08:14:48 Tina Ruchandani wrote:

struct timeval uses a 32-bit field for representing seconds, which will overflow in the year 2038 and beyond. This patch replaces struct timeval with 64-bit ktime_t which is 2038 safe. The patch is part of a larger effort to remove instances of 32-bit timekeeping variables (timeval, time_t and timespec) from the kernel.

The patch looks correct to me, just two minor points:

drivers/pci/xen-pcifront.c static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op) · line 137

Quoted 2 lines
drivers/pci/xen-pcifront.c +2 -0
+       tv = ktime_get_real();
+       ns_timeout = ktime_to_ns(tv) + 2 * (s64)NSEC_PER_SEC;

* We have a macro for doing this in one line, so you can just use

	ns_timeout = ktime_get_real_ns() + 2 * (s64)NSEC_PER_SEC;

* As the time is not stored anywhere and only used in a local function, using monotonic time instead of real time would slightly more appropriate, the only difference being the handling of a concurrent settimeofday() system call. That means calling ktime_get_ns() instead of ktime_get_real_ns().

Arnd

#4 lore raw
In reply to Tina Ruchandani
Quoted 6 lines · On Monday 11 May 2015 08:14:48 Tina Ruchandani wrote:

struct timeval uses a 32-bit field for representing seconds, which will overflow in the year 2038 and beyond. This patch replaces struct timeval with 64-bit ktime_t which is 2038 safe. The patch is part of a larger effort to remove instances of 32-bit timekeeping variables (timeval, time_t and timespec) from the kernel.

The patch looks correct to me, just two minor points:

drivers/pci/xen-pcifront.c static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op) · line 137

Quoted 2 lines
drivers/pci/xen-pcifront.c +2 -0
+       tv = ktime_get_real();
+       ns_timeout = ktime_to_ns(tv) + 2 * (s64)NSEC_PER_SEC;

* We have a macro for doing this in one line, so you can just use

	ns_timeout = ktime_get_real_ns() + 2 * (s64)NSEC_PER_SEC;

* As the time is not stored anywhere and only used in a local function, using monotonic time instead of real time would slightly more appropriate, the only difference being the handling of a concurrent settimeofday() system call. That means calling ktime_get_ns() instead of ktime_get_real_ns().

Arnd